The present invention relates to a sorting apparatus or a sorter for sorting sheet materials (hereinafter called "sheet") such as copy sheets, transfer sheets and recording sheets discharged from an image forming apparatus, e.g., a copying machine, a printing machine or other recording machines.
A sorter currently used includes ten-twenty or more sheet receiving plates (hereinafter called "trays"), each of which receives one-by-one the sheets sequentially discharged at regular intervals from a copying machine or the like. Such a sorter will be briefly described in conjunction with FIG. 1. A sheet P discharged by discharging rollers 1 and 1 of a copying machine C is advanced to an inlet of the sorter S disposed opposed to the copying machine, and guided to transporting rollers 3 and 3 by inlet guides 2 and 2. The transporting rollers 3 and 3 form a nip therebetween, to which a sheet receptor portion of one of the group of stacked trays 4 is opposed, so that the sheet is received on the tray. The transporting rollers 3 and 3 may be omitted by giving the transporting function also to the discharging rollers 1 and 1 of the copying machine C. Suppose that the sorter contains fifteen trays 4.sub.1, 4.sub.2, . . . , 4.sub.15, the trays except for the topmost and the bottommost trays are pivotably supported on tray supporting plates 5 which are located at the lateral sides thereof. The tray supporting plates 5, supporting the trays 4.sub.1, 4.sub.2, . . . , 4.sub.15, move upwardly intermittently so that the topmost tray 4.sub.1, the second tray 4.sub.2, . . . can sequentially receive the sheets advanced by the transporting rollers 3 and 3.
In this construction wherein the sheet receiving action starts from the topmost tray and takes place sequentially toward the bottom tray, the distance through which the tray group can move is as small as one-half of the height H of the sorter. Therefore, if the top face of the sorter is made at the same level as the top face of the copying machine C, the position of the inlet of the sorter is necessarily determined to be at about H/2 position. However, from the standpoint of facilitating the access of the operator to the sheets on the tray, the discharge tray of the copying machine is desirably to be located at an upper position. As the number of the trays of the sorter increases, the initial position of the sorter (e.g., non-sorting mode operation) is required to be positioned increasingly below the discharge tray of the copying machine, with the result that the operator has to stoop to access to the copy sheets.